1. Field of the Invention
This invention relates to a speed change control method for an automatic transmission in which a direct coupled clutch is provided in parallel to a fluid type torque converter, and the supply of oil pressure to a hydraulic servo for the direct coupled clutch and other friction engaging elements is controlled by an electromagnetic valve.
2. Description of the Prior Art
In such an automatic transmission, when vehicle speed exceeds a predetermined value, the direct coupled clutch is held in the engaging condition to prevent power losses in the fluid type torque converter. However, when an accelerator pedal is abruptly returned while the direct coupled clutch is in the engaged condition, transmission torque of a drive system changes abruptly to produce vibration in the drive system and a rough ride through the sway of car body.